Can't find installable ISAM What's wrong?

Question

Have some issue with importing Excel Documnet in dataGrid with access Database (ad.Fill(dt)). Can someone know how to fix it? Is the main problem due to an already loaded database or having two connections? Try to edit quetes, builds, but nothing no get result. Google this problem, but nothing similiar. Sorry for my stupidity.

public partial class dashboard : Form
{
    public static string ConnectString = "Provider = Microsoft.Jet.OLEDB.4.0; Data Source = Books.mdb";
    public OleDbConnection myConnection;
    
    
    public dashboard()
    {
        InitializeComponent();
        myConnection = new OleDbConnection(ConnectString);          
        myConnection.Open();
    }

    public void SendDataToGrid(params object[] data)
    {
        dataGridView1.Rows[dataGridView1.CurrentCell.RowIndex].SetValues(data);
        //Определяем индекс текущей строки, записываем в неё пришедшие значения 
    }
    
    private void dashboard_Load(object sender, EventArgs e)
    {
        Thread.CurrentThread.CurrentUICulture = new System.Globalization.CultureInfo("en-US");
 
        this.bookListTableAdapter.Fill(this.booksDataSet.BookList);

    }

    private void button1_Click(object sender, EventArgs e)
    {
        AddingForm addingform = new AddingForm(this);
        addingform.ShowDialog();
        
    }
   
    private void button2_Click(object sender, EventArgs e)
    {
        try
        {
            DialogResult dr = MessageBox.Show("Delete?", "Deleting", MessageBoxButtons.YesNo, MessageBoxIcon.Warning, MessageBoxDefaultButton.Button2);
            if (dr == DialogResult.Yes)
            {
                booksDataSet.BookList.Rows.Find(dataGridView1.CurrentRow.Cells[0].Value).Delete();
                bookListTableAdapter.Update(booksDataSet.BookList);
                booksDataSet.BookList.AcceptChanges();
            }
        }
        catch (Exception ex)
        {
            MessageBox.Show(ex.Message);
        }
    }

    private void button3_Click(object sender, EventArgs e)
    {
        EditForm editform = new EditForm(this);
        editform.ShowDialog();
    }

    private void button4_Click(object sender, EventArgs e)
    {
        dashboard_Load(sender, e);
    }
  

    private void dataGridView1_RowPrePaint(object sender, DataGridViewRowPrePaintEventArgs e)
    {
        int index = e.RowIndex;
        string indexStr = (index + 1).ToString();
        object header = this.dataGridView1.Rows[index].HeaderCell.Value;
        if (header == null || !header.Equals(indexStr))
            this.dataGridView1.Rows[index].HeaderCell.Value = indexStr;
    }

    Bitmap bitmap;
    private void button5_Click(object sender, EventArgs e)
    {
        int height = dataGridView1.Height;
        dataGridView1.Height = dataGridView1.RowCount * dataGridView1.RowTemplate.Height * 2;
        bitmap = new Bitmap(dataGridView1.Width, dataGridView1.Height);
        dataGridView1.DrawToBitmap(bitmap, new Rectangle(0, 0, dataGridView1.Width, dataGridView1.Height));
        printPreviewDialog1.PrintPreviewControl.Zoom = 1;
        printPreviewDialog1.ShowDialog();
        dataGridView1.Height = height;
    }

    private void printDocument1_PrintPage(object sender, System.Drawing.Printing.PrintPageEventArgs e)
    {
        e.Graphics.DrawImage(bitmap, 0, 0);
    }

    private void button6_Click(object sender, EventArgs e)
    {
        Process.Start(@"1.pdf");

    }

    protected override void OnPaintBackground(PaintEventArgs e)
    {
        using (LinearGradientBrush brush = new LinearGradientBrush(this.ClientRectangle,
                                                                  Color.White,
                                                                   Color.FromArgb(239, 247, 237),
                                                                   100000F))
        {
            e.Graphics.FillRectangle(brush, this.ClientRectangle);
        }
    }

    private void button7_Click(object sender, EventArgs e)
    {
        About about = new About(this);
        about.ShowDialog();
    }

    private void button8_Click(object sender, EventArgs e)
    {
        Excel.Application exAAP = new Excel.Application();
        exAAP.Workbooks.Add();
        Excel.Worksheet wsh = (Excel.Worksheet)exAAP.ActiveSheet;
        int i, j;
        for (i = 0; i <= dataGridView1.RowCount - 2; i++)
        {
            for (j = 0; j <= dataGridView1.ColumnCount - 1; j++)
            {
                wsh.Cells[i + 1, j + 1] = dataGridView1[j, i].Value.ToString();

            }
        }

        exAAP.Visible = true;
    }
   
    private void button9_Click(object sender, EventArgs e)
    {
        OpenFileDialog opn = new OpenFileDialog();
        if (opn.ShowDialog() == System.Windows.Forms.DialogResult.OK)
        {
            this.textBox1.Text = opn.FileName;
        }
    }

    public void button10_Click(object sender, EventArgs e)
    {
        string path = "provider=microsoft.jet.OLEDB.4.0;Data source =" + textBox1.Text + ";Extended properties=\"Excel.8HDR=yes;\"; ";
        OleDbConnection  ExcelConnection = new OleDbConnection(path);
        OleDbDataAdapter ad = new OleDbDataAdapter("select * from [" + textBox2.Text + "$]", ExcelConnection);
        DataTable dt = new DataTable();
        ad.Fill(dt); //Error trigger!
        dataGridView1.DataSource = dt;
    }
}